Densities of active species in N2 and N2–H2 RF pink afterglow

Abstract

The transverse distribution of N2 radiative states has been analyzed in the early afterglow of RF N2 flowing discharge with the introduction of a few H2 molecules (10−5–10−3) in the discharge. The transverse distributions of N2, 1st (580 nm), 2nd pos (316 nm) and ,1st neg (391.4 nm) band intensities have a sharp profile in pure N2. As more H2 was introduced into N2, a sharper profile for the ,1st neg was observed, and inversely a broader profile for the N2, 1st pos. With the introduction of H2 into N2 the early afterglow was changed from a sharp pink to a broad late afterglow where the N + N recombination is the dominant process. After NO titration of N-atom density in pure N2 late afterglow, the variation of N-atom and N2(A) density in the N2–H2 early afterglow is deduced. The N2(X, v > 13) density is also estimated.